2,416 research outputs found

    Folding and Unfolding in the Blue Copper Protein Rusticyanin: Role of the Oxidation State

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    The unfolding process of the blue copper protein rusticyanin has been studied from the structural and the thermodynamic points of view at two pH values (pH 2.5 and 7.0). When Rc unfolds, copper ion remains bound to the polypeptide chain. Nuclear magnetic resonance data suggest that three of the copper ligands in the folded state are bound to the metal ion in the unfolded form, while the other native ligand is detached. These structural changes are reflected in the redox potentials of the protein in both folded and unfolded forms. The affinities of the copper ion in both redox states have been also determined at the two specified pH values. The results indicate that the presence of two histidine ligands in the folded protein can compensate the change in the net charge that the copper ion receives from their ligands, while, in the unfolded protein, charges of aminoacids are completely transferred to the copper ion, altering decisively the relative stability of its two-redox states

    Respuesta ósea al implante del compuesto beta-fosfato tricálcico-colágeno (ß-ftc-c). Estudio «in vivo» en conejos

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    Se ha estudiado la correlación entre los hallazgos histológicos y las imágenes radiológicas de un compuesto de beta-fosfato tricálcico y colágeno (ß-FTC-C) después de su implantación en defectos óseos creados experimentalmente en 21 conejos de 4 Kg de peso medio. Bajo anestesia general los defectos óseos creados en ambos fémures se rellenaron con un cilindro de 4,5 x 6 mm del compuesto. Los animales fueron sacrificados a la semana y 1, 2, 4 y 12 meses del postoperatorio. Las muestras obtenidas fueron sometidas a estudio radiográfico e histológico. Microscópicamente se comprobó que el compuesto a lo largo del período de implantación sufrió un proceso de reabsorción progresiva mediado por células de estirpe macrofágica y que se correspondió con una disminución de la densidad radiológica y cambios en su morfología. A los doce meses del postoperatorio se observaron escasos restos del material, hecho que se corresponde con la desaparición del implante en la placa radiográfica.The correlation between histologic and radiological findings was studied after implantation of a composite (ß-FTC-C) into osseus defects which were experimentally induced in 21 rabbits. Under general anaesthetic osseus defects were made in both femurs and filled in with a 4,5 x 6 mm composite cylinder. The animals were killed at the first week and, one, two, four and twelve months after surgery. X-ray study and microscopic examination were made in all the specimens. Troughout the implantation period, it was microscopically proven that the composite showed a progressive reabsortion process, mediated by cells of macrophagus lineage. A decrease in radiologic density and changes in its morphology were also observed. At the end of the study (twelve months), limited traces of the material could be seen, in correlation with the images of the X-ray films which revealed the total absence of the composite implant

    Severe Acute Respiratory Syndrome Coronavirus Envelope Protein Ion Channel Activity Promotes Virus Fitness and Pathogenesis

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    Deletion of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) envelope (E) gene attenuates the virus. E gene encodes a small multifunctional protein that possesses ion channel (IC) activity, an important function in virus-host interaction. To test the contribution of E protein IC activity in virus pathogenesis, two recombinant mouse-adapted SARSCoVs, each containing one single amino acid mutation that suppressed ion conductivity, were engineered. After serial infections, mutant viruses, in general, incorporated compensatory mutations within E gene that rendered active ion channels. Furthermore, IC activity conferred better fitness in competition assays, suggesting that ion conductivity represents an advantage for the virus. Interestingly, mice infected with viruses displaying E protein IC activity, either with the wild-type E protein sequence or with the revertants that restored ion transport, rapidly lost weight and died. In contrast, mice infected with mutants lacking IC activity, which did not incorporate mutations within E gene during the experiment, recovered from disease and most survived. Knocking down E protein IC activity did not significantly affect virus growth in infected mice but decreased edema accumulation, the major determinant of acute respiratory distress syndrome (ARDS) leading to death. Reduced edema correlated with lung epithelia integrity and proper localization of Na+ /K+ ATPase, which participates in edema resolution. Levels of inflammasome-activated IL-1b were reduced in the lung airways of the animals infected with viruses lacking E protein IC activity, indicating that E protein IC function is required for inflammasome activation. Reduction of IL-1b was accompanied by diminished amounts of TNF and IL-6 in the absence of E protein ion conductivity. All these key cytokines promote the progression of lung damage and ARDS pathology. In conclusion, E protein IC activity represents a new determinant for SARS-CoV virulence

    Small RNAs of Haloferax mediterranei: Identification and Potential Involvement in Nitrogen Metabolism

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    Small RNAs have been studied in detail in domains Bacteria and Eukarya but, in the case of the domain Archaea, the knowledge is scarce and the physiological function of these small RNAs (sRNAs) is still uncertain. To extend the knowledge of sRNAs in the domain Archaea and their possible role in the regulation of the nitrogen assimilation metabolism in haloarchaea, Haloferax mediterranei has been used as a model microorganism. The bioinformatic approach has allowed for the prediction of 295 putative sRNAs genes in the genome of H. mediterranei, 88 of which have been verified by means of RNA-Sequencing (RNA-Seq). The secondary structure of these sRNAs and their possible targets have been identified. Curiously, some of them present as possible target genes relating to nitrogen assimilation, such as glutamate dehydrogenase and the nitrogen regulatory PII protein. Analysis of RNA-Seq data has also revealed differences in the expression pattern of 16 sRNAs according to the nitrogen source. Consequently, RNomic and bioinformatic approaches used in this work have allowed for the identification of new sRNAs in H. mediterranei, some of which show different expression patterns depending on the nitrogen source. This suggests that these sRNAs could be involved in the regulation of nitrogen assimilation and can constitute an important gene regulatory network.This work was supported by grant BIO2013-42921-P from the Spanish Ministry of Economy and Competitiveness. Funds from “Programa Propio para el fomento de la I+D+i del Vicerrectorado de Investigación y Transferencia de Conocimiento” de la Universidad de Alicante are also acknowledged

    Diseño y validación de un instrumento de observación de las conductas que alteran la convivencia en educación física

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    El objetivo del presente trabajo fue diseñar y validar un instrumento de observación de conductas que alteran la convivencia en las clases de Educación Física, que permita definirlas, categorizarlas y medirlas cuantitativamente. Este proceso de validación se llevó a cabo en varias fases y contó con la participación de seis jueces expertos en el ámbito de la enseñanza de la Educación Física y cuatro observadores formados en el análisis de las conductas que alteran el clima de convivencia en las clases de Educación Física. Observaron un total de diez clases de Educación Física, de sexto de Educación Primaria y de tercero de la Educación Secundaria de diez centros escolares diferentes, analizando la estructura del instrumento mediante procedimientos confirmatorios. El instrumento final estuvo formado por ocho conductas que alteran la convivencia en las clases de Educación Física, agrupadas en dos factores (conductas violentas y conductas de indisciplina y desinterés). Los resultados obtenidos en el proceso de validez, fiabilidad y consistencia interna indican que el instrumento diseñado es válido para registrar las conductas que alteran la convivencia en las clases de Educación Física y permite su aplicación sin la presencia del observador en el aula, minimizando así el efecto de esa presencia en el comportamiento del alumnado.The aim of this study was to design and validate an instrument of observation that would allow us to measure and quantify student misconduct during classes of physical education. This process of validation was carried out in several phases. Six expert judges in physical education teaching and four observers trained to measure student misconduct in physical education lessons participated in the process, analysing ten physical education lessons of sixth and ninth grade from ten different schools, settings the structure of the instrument through confirmatory procedures. The final instrument consisted of eight items describing different kinds of student misconduct during physical education classes, grouped into two categories (violent behaviours and undisciplined and disinterested behaviours). The results obtained in the process of validation, reliability and internal consistency suggest that the instrument designed is optimally useful and reliable to measure student misconduct during physical education classes, allowing its application without the presence of the investigator in the classroom, thus minimizing its effect on the behaviour of the student body

    Quaternary fossil horses within the Prados-Guatén Depression (Pantoja de La Sagra, Toledo)

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    Durante la primera reunión de campo del Grupo Madrileño de Cuaternario (GQM-AEQUA) se localizaron restos fragmentarios de dentición de caballos fósiles en los antiguos areneros de Pantoja de La Sagra (Toledo), actualmente en proceso de desmantelamiento y relleno. Ante la posibilidad de deterioro y pérdida los restos fueron recolectados y trasladados al Museo Nacional de Ciencias Naturales (CSIC, Madrid) donde se ha procedido a su análisis. Las piezas fósiles analizadas responden a un maxilar izquierdo con tres piezas dentales in situ (molares y premolares), y otras siete más aisladas. Todos los dientes aislados, junto con el fragmento de maxilar existente, corresponden a un adulto joven. Los restos fósiles se encontraban asociados a un nivel de arenas fluviales situado unos cuatro metros por debajo de la superficie de la Terraza de +15 m de la Depresión Prados-Guatén definida como un nivel perteneciente al tránsito Pleistoceno inferior-medio, del antiguo Sistema fluvial Manzanares-Guatén por Silva (1988). En concreto los niveles superiores de esta terraza han sido interpretados como resultado de la superposición de los últimos depósitos del antiguo sistema fluvial y los primeros asociados al relleno de la Depresión por tributarios de área fuente más local tras su abandono como consecuencia del proceso de captura del valle inferior del Manzanares por parte del Río Jarama al SW de la Ciudad de Madrid (Silva et al., 1988). Los caracteres morfológicos y morfométricos de las piezas dentarias permiten identificarlos como Equus ferus cf. mosbachensis cuya distribución bioestratigráfica abarca la parte final del Pleistoceno Medio (c.a. 500-200 ka B.P.). Junto a los restos fósiles aparecieron también escasos fragmentos líticos correspondientes a productos de lascado en sílex de difícil atribución tecnológica. Los restos fósiles analizados, indican que el depósito extensivo de arenas fluviales en el eje de la Depresión, culminó durante el final del Pleistoceno medio, y que la dinámica fluvial de la Depresión tras su proceso de abandono fue de hecho más activa de lo que se pensaba con la instalación de sistemas de arroyos relevantes alimentados por cabeceras locales antes del encajamiento definitivo actual de los arroyos Prados y Guatén.During the first field-meeting of the Madrid Quaternary Research Group (GQM-AEQUA) several fossil teeth remnants of horses were localised at the ancient sand-quarries of Pantoja de La Sagra (Toledo), which presently are abandoned and refilling in progress. The possibility of deterioration and loss of the localised fossils remnants induced by the quarry works, they were collected and taken away to the Museo Nacional de Ciencias Naturales (CSIC, Madrid) for their preservation and analysis. Fossil remains correspond to a left maxilla with two in situ molars, another one inset on its alveolar cavity, fragments of premolar cavities, as well as other seven more isolated teeth. These fossils were outcropping in a sandy level at four meters below the +15 m fluvial terrace surface of the axial sector of de Prados-Guatén Depression, which is considered the last fluvial level belonging to the ancient Manzanares-Guatén fluvial system during the Lower-Middle Pleistocene transit (Silva, 1988). In detail, the upper fluvial sediments of this particular terrace level were interpreted as the result of the overlapping between the last materials deposited by the ancient Manzanares-Guatén fluvial system and the first ones resulting from the readjustment of former tributaries after the abandonment of the Depression caused by fluvial capture of the Lower Manzanares Valley SW Madrid City. The morphological features of the oclusal surface of the horse teeth and morphometric comparative analyses indicate that they belong to the specie Equus ferus, and probably to the subspecie mosbachensis. However due to the bad definition of this group in Europe and the few individuals analysed the better classification is Equus ferus cf. mosbachensis. The bioestratigraphic distribution of this fossil horse group in Europe extends on the upper part of the Middle Pleistocene (c.a. 500-200 ka B.P.). Few lithic artefacts outcropped also associated to the fossil remains, constituted by laminar flakes of hard technological classification. Fossil remains analysed in this work joint to the unique previous quaternary fossil mammal described for the Prados-Guatén Depression constituted by Mammuthus meridionalis NESTI of the former quarry of Esquivias adjacent to the AVE railway line (Silva et al., 1988b; 1999). The chronostratigraphic attribution of the fossil horses (Upper Middle Pleistocene) described here indicate that fluvial sedimentary activity within the Depression was relevant after its abandonment. Ancient tributaries of the former Manzanares-Guatén fluvial system, feed by local-intrabasinal headwaters, reworked the previous sandy sediments triggering multiepisodic deposition during the upper part of the Middle Pleistocene, before the more recent eventual incision of present streams dissecting the Depression

    Biochemical markers of bone turnover and clinical outcome in patients with renal cell and bladder carcinoma with bone metastases following treatment with zoledronic acid: The TUGAMO study

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    Background: Levels of bone turnover markers (BTM) might be correlated with outcome in terms of skeletal-related events (SRE), disease progression, and death in patients with bladder cancer (BC) and renal cell carcinoma (RCC) with bone metastases (BM). We try to evaluate this possible correlation in patients who receive treatment with zoledronic acid (ZOL). Methods: This observational, prospective, and multicenter study analysed BTM and clinical outcome in these patients. Serum levels of bone alkaline phosphatase (BALP), procollagen type I amino-terminal propeptide (PINP), and beta-isomer of carboxyterminal telopeptide of type I collagen (b-CTX) were analysed. Results: Patients with RCC who died or progressed had higher baseline b-CTX levels and those who experienced SRE during follow-up showed high baseline BALP levels. In BC, a poor rate of survival was related with high baseline b-CTX and BALP levels, and new SRE with increased PINP levels. Cox univariate analysis showed that b-CTX levels were associated with higher mortality and disease progression in RCC and higher mortality in BC. Bone alkaline phosphatase was associated with increased risk of premature SRE appearance in RCC and death in BC. Conclusion: Beta-isomer of carboxy-terminal telopeptide of type I collagen and BALP can be considered a complementary tool for prediction of clinical outcomes in patients with BC and RCC with BM treated with ZOLNovartis Oncology Spain for supporting this stud
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